1. Field of the Invention
The present invention relates to a rotary-type magnetic recording medium on which servo patterns are formed in servo pattern regions on at least one surface of a disk-shaped substrate by patterns including recording regions and non-recording regions, to a recording/reproducing apparatus that includes such magnetic recording medium, and to a stamper for manufacturing such magnetic recording medium.
2. Description of the Related Art
As one example of this type of magnetic recording medium, Japanese Laid-Open Patent Publication No. 2006-277869 discloses a discrete track medium where concave/convex patterns constructed by a ferromagnetic layer are formed in both servo regions (servo pattern regions) and data regions (data recording regions) and where concaves in the concave/convex patterns are filled with non-magnetic material so as to be smoothed as a whole. On the discrete track medium disclosed as a conventional magnetic disk in the above publication, data regions in which recording tracks are constructed by the convexes in the concave/convex patterns mentioned above and servo regions in which servo patterns are constructed by the concave/convex patterns mentioned above are defined so as to be alternately positioned in the direction of rotation of the discrete track medium. In each servo region, a preamble region (preamble pattern region), an address region (address pattern region), and burst regions (burst pattern regions) are defined so as to be adjacent in the direction of rotation of the discrete track medium. On the other hand, on a discrete track medium according to an embodiment of the invention disclosed in the publication, a data region is defined at at least one position out of a position between a preamble region and an address region, a position between the address region and the burst regions, and a position between an AB burst region and a CD burst region in the burst regions.
On the two discrete track media described above, burst patterns including a plurality of burst signal units (each of which is a concave that is recognized as “one non-recording region” in a burst region) that are rectangular in planar form (i.e., rectangular when viewed from above) are formed by concave/convex patterns in the burst regions. In the burst pattern formed in the AB burst region, the outer periphery-side edges of burst signal units formed in the A burst region and inner periphery-side edges of burst signal units formed in the B burst region are both linearly formed so that the distance from the center of the discrete track medium is equal, and inner periphery-side edges of burst signal units formed in the A burst region and outer periphery-side edges of burst signal units formed in the B burst region are both linearly formed so that the distance from the center is equal. In addition, in the burst pattern formed in the CD burst region, outer periphery-side edges of burst signal units formed in the C burst region and inner periphery-side edges of burst signal units formed in the D burst region are both linearly formed so that the distance from the center is equal, and inner periphery-side edges of burst signal units formed in the C burst region and outer periphery-side edges of burst signal units formed in the D burst region are both linearly formed so that the distance from the center is equal.
In the burst patterns formed in each burst region, a leading edge and a trailing edge in the direction of rotation of each burst signal unit are both linearly formed. On such discrete track media, the length along the direction of rotation of the burst signal units (i.e., concaves), or in other words, the distance between both edges along the radial direction of the discrete track medium, and the length along the direction of rotation of the gap (i.e., convex) between two burst signal units that are adjacent in the direction of rotation, or in other words, the distance between the leading edge of one burst signal unit and the trailing edge of another burst signal unit, are formed so as to be substantially 1:1.